Philadelphia mafia boss Joseph"Skinny Joey" Merlino -- who served 12 years
in federal prison for racketeering -- says the guys from "Jersey Shore"
are a big, fat "disgrace to the Italians" ... seriously.

Merlino
-- who was released from the slammer last year -- was at LAX yesterday,
where he was picked up from the airport by Howard Stern's favorite mob
family member Johnny Fratto.

It's unclear why Joey is in L.A. --
but as Johnny drove off with Merlino riding shotgun, he picked an
interesting song choice to bump in his car ... Elton John's
"Philadelphia Freedom."

FYI -- Merlino was rumored to have been a
heavy gambler before he got locked up ... and when we asked if he had
any advice for Harvey (who's been getting killed with his NFL picks) ...
"Skinny Joey" had one solid piece of advice ... and it involves one
Thomas Edward Patrick Brady.